"It's a relic of an age of prejudice and insufficient understanding,'' the attorney general said in prepared remarks set for delivery Tuesday evening to Lambda Legal, an advocacy group for LGBT rights.

Referring to the group's work a decade ago to challenge the termination of a gay assistant scoutmaster, Holder said that "too many organizations, policies and practices that discriminate against LGBT individuals remain persistent concerns.''

"Unfortunately, the continuation of a policy that discriminates against gay adult leaders – by an iconic American institution – only preserves and perpetuates the worst kind of stereotypes,'' he said.

In 2013, the Boy Scouts voted to allow gay youths to join its activities, but refused to budge on a ban against gay leaders. Boy Scouts leader Robert Gates, who oversaw the dismantling of "Don't Ask Don't Tell" during his stint as Secretary of Defense, addressed the issue at last year's national council stating he supported a change but didn't feel the time was right.

Holder obviously objects to that idea. "If these men and women are fit for military service, then surely they are fit to mentor, to teach, and to serve as role models for the leaders of future generations," said Holder.